This invention concerns improvements in or relating to stationery. The invention has particular application to stationery forms comprising a single sheet of paper which may be printed and folded about one or more crease lines to conceal the printing and secure the form in a folded condition by means of adhesive whereby the form may be sent through the post without requiring the use of a separate envelope.
Forms of this type are known in which the adhesive is applied as a continuous strip around the marginal edge of the form clear of the printable region of the form.
The adhesive may be water activated such as a gum which the user wets, e.g. by licking, and then presses to seal the form in the folded condition by finger pressure applied to the adhesive region of the folded form.
Alternatively, the adhesive may be self-sealing such as a contact adhesive which does not require wetting or any other activation prior to sealing. The contact adhesive may be a low pressure type which permanently seals the form in the folded condition when finger pressure is applied to the adhesive region of the folded form. This is suitable for manual sealing of the form where the number of forms to be sealed is small. Where the number of forms to be sealed is large such as for business use, it is usual to employ a sealing machine to automatically seal the forms in the folded condition.
Such machines can be designed to apply a much higher sealing force than is possible manually with a finger. As a result, a high-pressure type contact adhesive may be employed which permanently seals the form in the folded condition when sufficient pressure is applied but does not seal under finger pressure thereby reducing the risk of accidental or inadvertent sealing of the forms by finger pressure and/or of the forms sticking to each other.
A disadvantage of the known contact adhesives is that once the form is permanently sealed in the folded condition, either manually by finger pressure or automatically by machine pressure, the form can only be opened by removing the adhesively bonded regions from the rest of the form. This is usually effected by the provision of lines of weakness inboard of the adhesive so the adhesively bonded regions can be easily separated from the rest of the form. As a result, the form cannot be opened and re-sealed to make additions or alterations to the printed information after the form has been folded and sealed.
Yet another disadvantage is that when sealing the form in the folded condition, air can be trapped in the folded form and prevented from escaping by the continuous seal provided by the adhesive applied around the entire marginal edge of the form. This trapped air causes bulging of the folded and sealed form which, in turn, makes the form susceptible to tearing or other damage so as to make the printing applied to the form illegible and/or render the form unusable for its intended purpose. This is a particular problem if the form is intended to be completed with information by the recipient and returned to the sender.
Thus, it is an object of the present invention to provide a stationery form which can be sealed temporarily in a folded condition to allow the form to be opened and re-sealed if required and which can also be sealed permanently in the folded condition to prevent the form being opened until the adhesively bonded regions have been separated from the rest of the form.
It is yet another object of the present invention to provide a stationery form which can be folded and sealed temporarily or permanently in a folded condition without air being permanently trapped in the folded and sealed form until the form is opened and/or otherwise ruptured to release the air. Thus, according to a first aspect of the invention, there is provided a stationery form comprising a single sheet of paper or similar printable material to which a self-seal contact adhesive is applied so that adhesive regions contact and adhere releasably to each other when the form is folded and a first pressure applied to the contacting adhesive regions to seal temporarily the form in a folded condition, and which adhere non-releasably to each other when a second pressure higher than the first pressure is applied to the contacting adhesive regions to seal permanently the form in the folded condition.
By this invention, the contact adhesive provides a dual function to temporarily seal the form when a low pressure is applied, for example manually with a finger, that allows the form to be opened and re-sealed, and to permanently seal the form when a high pressure is applied, for example automatically with a sealing machine, that requires separation of the adhesively bonded regions to open the form.
In this way, the user can select whether to seal the form temporarily or permanently. Where the form is sealed temporarily, the form can be opened and re-sealed allowing additions or alterations to be made to the printed information by the sender and/or by the receiver without scrapping forms which have already been sealed. Thus, it is envisaged that the sender may seal the form temporarily to allow the recipient to open the form, add information and then seal permanently the form for return to the sender. In this way, unauthorised access to the information added by the recipient is prevented.
According to a second aspect of this invention, there is provided a stationery form comprising a single sheet of paper or similar printable material to which a self-seal contact adhesive is applied so that adhesive regions contact and adhere to each other when the form is folded to seal the form in a folded condition wherein the adhesive is applied as a discontinuous border strip leaving adhesive free regions which are aligned in the folded condition of the form to define one or more gaps between adhesively secured regions so as to allow air trapped in the folded and sealed form to escape.
By this invention, the form can be flattened after folding and sealing to expel trapped air through the gaps provided in the adhesively secured regions of the form. Thus, the simple expedient of providing the adhesive as a discontinuous strip avoids the problems of the prior art stationery forms while still enabling the form to be sealed in a folded condition suitable to be sent through the post. The adhesive may be chosen so that the form can be sealed either temporarily or permanently in accordance with the first aspect of the invention.
According to a third aspect of this invention, there is provided a stationery form comprising a single sheet of paper or similar printable material to which a self-seal contact adhesive is applied so that adhesive regions contact and adhere to each other when the form is folded to seal the form in a folded condition wherein the form is provided with a first window arranged to align with a first printable region of the form in the folded condition and a second window arranged to align with a second printable region of the form in the folded condition.
By this invention, the first and second printable regions can be printed with the addresses of the recipient and the sender at the same time the form is printed with the information to be sent to the recipient and both addresses are visible through the associated window in the folded condition of the form. As a result, the form can be printed in a single operation and, when sealed, a return address is provided which allows the form to be returned to the sender if the recipient has moved. The adhesive may be chosen so that the form can be sealed either temporarily or permanently in accordance with the first aspect of the invention, and/or the adhesive may be applied to prevent air being trapped in the folded condition of the form in accordance with the second aspect of the invention.
In a preferred embodiment according to each of the aspects of the invention, the form is designed to be folded in half when it is desired to close and seal the form in the folded condition. For this, the form is provided with a single crease or fold line across the centre between the side edges mid-way between the top and bottom of the form.
In this way, the edges of the top half are aligned with the edges of the bottom half and the contact adhesive is applied as a narrow border strip or band adjacent to the edges. As a result, the adhesive on the bottom half contacts and sticks to the adhesive on the top half when the form is folded about the crease line and pressure applied to the aligned adhesive regions.
It is desirable in each aspect of the invention that the forms can be stacked on top of each other in the unfolded condition without sticking to each other. In this way, a printer can be used to print the desired information on the forms which are supplied to the printer from a stack without risk of two or more forms becoming stuck together accidentally and jamming the printer feed.
The adhesive is preferably chosen so that an adhesive region will only stick to another adhesive region and, when the forms are stacked on top of each other in the unfolded condition, an adhesive region on one form does not contact an adhesive region on an adjacent form.
Where the form is designed to be folded in half, the adhesive is applied to the marginal edges on one side of the form only thereby allowing the forms to be stacked on top of each other without contact between the adhesive regions.
For forms which may be designed to be folded more than once, the adhesive may be applied to the marginal edges on both sides of the form and in this case, the adhesive regions on one side are preferably arranged to be offset from the adhesive regions on the other side so that the forms can be stacked without contact between the adhesive regions.
Preferably, the stationery form and the contact adhesive according to each of the aspects of the invention are selected to be compatible with most laser printers but it will be understood that the forms and adhesive may be chosen for use with other types of printers, e.g. inkjet or bubblejet printers.
Advantageously, the stationery form according to each aspect of the invention has a window arranged to align with a part of the form on which the name and address of a recipient of the form is placed so as to be visible through the window in the folded condition of the form. In this way, the details of the recipient can be printed on the form at the same time the form is printed with the information to be sent to the recipient in a single operation.
More preferably, however, the form is provided with two windows arranged to align with separate printable regions of the form in the folded condition whereby the addresses of both the recipient and the sender may be printed and visible through the associated window in the folded condition. In this way, the form can be returned to the sender either if the recipient has moved or if the form can be opened and re-sealed by the recipient to include information added to the form by the recipient.
The invention together with the benefits and advantages will be more fully understood from the description of exemplary embodiments later herein of the stationery form which I prefer to call xe2x80x9cMaster Mailerxe2x80x9d. It will be understood however that such description is not intended to be exhaustive of all possible applications and uses of the invention and that various modifications can be made without departing from the spirit and scope of the invention.